Evidence for Limited Early Spread of COVID-19 Within the United States, January–February 2020

作者：CDC COVID-19 Response Team, Michelle A. Jorden, Sarah L. Rudman, Elsa Villarino, Stacey Hoferka, Megan Toth Patel, Kelley Bemis, Cristal R. Simmons, Megan Jespersen, Jenna Iberg Johnson, Elizabeth Mytty, Katherine D. Arends, Justin J. Henderson, Robert W. Mathes, Charlene X. Weng, Jeffrey S. Duchin, Jennifer L. Lenahan, Natasha S. Close, Trevor Bedford, Michael Boeckh, Helen Y. Chu, Janet A. Englund, Michael Famulare, Deborah A. Nickerson, Mark J. Rieder, Jay Shendure, Lea M. Starita, CDC COVID-19 Response Team, Gregory L. Armstrong, Jay C. Butler, Michael A. Coletta, Aaron Kite-Powell, Julu Bhatnagar, Sarah Reagan-Steiner, Suxiang Tong, Brendan L. Flannery, Jill M. Ferdinands, Jessie R. Chung · 发表于：MMWR Morbidity and Mortality Weekly Report · 年份：2020 · DOI：10.15585/mmwr.mm6922e1 · 被引用次数：189 · 研究领域：COVID-19 epidemiological studies、COVID-19 Clinical Research Studies、COVID-19 Pandemic Impacts

From January 21 through February 23, 2020, public health agencies detected 14 U.S. cases of coronavirus disease 2019 (COVID-19), all related to travel from China (1,2). The first nontravel-related U.S. case was confirmed on February 26 in a California resident who had become ill on February 13 (3). Two days later, on February 28, a second nontravel-related case was confirmed in the state of Washington (4,5). Examination of four lines of evidence provides insight into the timing of introduction and early transmission of SARS-CoV-2, the virus that causes COVID-19, into the United States before the detection of these two cases. First, syndromic surveillance based on emergency department records from counties affected early by the pandemic did not show an increase in visits for COVID-19-like illness before February 28. Second, retrospective SARS-CoV-2 testing of approximately 11,000 respiratory specimens from several U.S. locations beginning January 1 identified no positive results before February 20. Third, analysis of viral RNA sequences from early cases suggested that a single lineage of virus imported directly or indirectly from China began circulating in the United States between January 18 and February 9, followed by several SARS-CoV-2 importations from Europe. Finally, the occurrence of three cases, one in a California resident who died on February 6, a second in another resident of the same county who died February 17, and a third in an unidentified passenger or crew memb...